In the field of multi-spectral detection of a hybridized component, that is, capable of detecting a plurality of wavelength ranges, it is known to add an optical filter fixing, due to the performed filtering, said wavelength ranges.
In so-called cooled infrared detection, that is, implementing quantum technology, such a filter may be attached to the cryostat or to the cold shield. In known fashion, the former cools down the detector to allow the operation thereof. The latter limits parasitic optical flows on the detector.
Such a technology does not enable to index and functionalize each of the photosites forming the detection array. The optical elements at the level of the cryostat or of the cold shield only allow a functionalizing of all the photosites of said array.
It has already been provided as an alternative technology to place the filter directly on the hybridized component, and particularly on the incident surface thereof, that is, the surface receiving the incident radiation to be detected.
Independently from the way in which such an optical element is attached to the back side, a real issue resulting from the alignment of the additional technological level relative to each of the photosites formed within the detection circuit is raised. This issue is all increased by the fact that said photosites may be functionalized independently from one another. Indeed, if the alignment of such an additional technological level relative to the detection sites is not correct, each of the sites is capable of receiving different wavelengths of the incident radiation, then affecting the result of the detection, and accordingly the quality of the signal.
According to prior art, the alignment of a technological level on a component is performed by alignment techniques in visible or near infrared imaging. In such wavelength ranges, the alignment of the additional technological level on the photosites may be performed by optical systems in the visible or near infrared range.
The invention is more specifically dedicated to infrared detectors having cut-off wavelengths higher than 1.7 micrometer, for which usual techniques cannot be used.
The object of the present invention thus is to provide a solution enabling to overcome this alignment issue, be it a filter-type optical system, or also the implementation of an additional technological level of metal mesh type.